Spin-entanglement of an atomic pair through coupling to their thermal motion

TL;DR

This study demonstrates that two atoms can become entangled through their thermal motion in an optical tweezer, challenging the notion that hot environments only destroy entanglement and showing potential for quantum sensing enhancements.

Contribution

The paper experimentally shows entanglement generation between two atoms via thermal motion coupling, a novel mechanism contrary to typical decoherence effects.

Findings

Initially unentangled spins become entangled through thermal motion.

Entanglement can enhance measurement sensitivity beyond standard quantum limits.

Thermal motion coupling can be a robust entanglement resource.

Abstract

The spin-dynamics of two alkali atoms in an optical tweezer is driven by spin-changing collisions that couple the spin-state of the atoms to their relative motion. This paper experimentally studies the resulting spin-states when the relative motion is in a thermal state with k B T much larger than the energies of the spin-states that take part in the dynamics. We find that an initially unentangled spin-state can evolve into an entangled state. This is contrary to the common case when coupling a quantum system to hot degrees of freedom leads to loss of entanglement and not its generation. Moreover, we show that the generated entanglement is technologically useful as it, in principle, can enhance the sensitivity of measurements beyond the standard quantum limit. This may provide a promising avenue for robust entanglement generation for future technologies.